The present invention relates to the diagnostic imaging arts. It finds particular application in conjunction with diagnostic imaging in open MRI scanners for oncology treatment applications and will be described with particular reference thereto. It will be appreciated, however, that the invention is also applicable to other types of diagnostic imaging for oncological purposes and for diagnostic imaging for other purposes.
In oncological planning, the oncologist typically determines a point of entry on the patient""s skin and a trajectory through the patient. Typically, the oncologist plans a trajectory and the point of entry in conjunction with projection x-ray images, CT scanner images, or other diagnostic images.
One of the difficulties encountered in oncological procedures is accurately aligning the x-ray beam with the internal tumor. If the selected trajectory is only slightly off, the x-ray beam will treat most of the tumor, but leave a small segment un-irradiated. Un-irradiated tumor tissue can survive the treatment.
Once the point of entry and the trajectory have been determined, the oncologist points an x-ray beam to enter the patient at the selected point of entry and follow the selected trajectory. Ideally, the x-ray beam is selected to have a diameter at least as large as the tumor to be irradiated. Making the diameter of the beam too large is detrimental in that it irradiates and harms healthy tissue.
Typically, the treatment process is repeated through a plurality of different trajectories to maximize the radiation at the tumor while minimizing radiation through surrounding tissue. In many instances, the tumor is over-irradiated to assure that portions of the tumor which might be missed along some trajectories are still fully irradiated. This over-radiation, like using a beam that is too large, has a detrimental effect on surrounding tissue.
Typically, x-ray images are used to generate the diagnostic images. X-ray images are advantageous in that they image the entire patient contour, including the surface boundaries facilitating selection of the point of entry. Unfortunately, it is sometimes difficult to differentiate between tissue types, such as cancerous and non-cancerous tissue with x-rays. Magnetic resonance imaging has much better differentiation of tissue types. However, magnetic resonance images tend to be of smaller, internal regions and often do not include the patient surface. When a larger region is imaged that includes the patient surface, peripheral portions of the image tend to be warped or distorted. Selecting the point of entry based on a warped or distorted image can cause mis-alignment between the beam and the cancerous tumor which, as discussed previously, can create the unwanted destruction of healthy tissue.
The present invention provides a new and improved method and apparatus which overcomes the above-referenced problems and others.
In accordance with one aspect of the present invention, a diagnostic imaging system is provided. A medical diagnostic imaging apparatus generates volumetric diagnostic image representations of an internal region of a subject in an imaging region. A surface imaging system generates a three-dimensional image representation of the surface of the subject in the imaging region. An image correlating system correlates the surface and diagnostic image representations. A superimposed volumetric image representation memory stores combined correlated surface and diagnostic image representations. A video processor withdraws selected portions of the combined image representation and converts them into appropriate form for human-readable display.
In accordance with another aspect of the present invention, a method of diagnostic imaging is provided. A volumetric diagnostic image representation of an internal region of a subject and at least a portion of a surface of the subject is generated. However, the diagnostic image representation has distortions, particularly in a region adjacent the surface of the subject. A surface imaging system generates a three-dimensional image representation of the surface of the subject. The diagnostic image representation is adjusted to correlate at least the surface region of the diagnostic image representation with the surface image representation. The adjusted diagnostic image representation and the surface image representation are combined.
One advantage of the present invention resides in its improved differentiation of soft tissue.
Another advantage of the present invention is that it facilitates a reduction in radiation doses in oncological treatments.
Another advantage of the present invention is that it facilitates location of internal patient structures from the exterior of the patient based on diagnostic images.
Another advantage of the present invention is that it reduces total patient radiation dose relative to x-ray and CT diagnostic imaging techniques.
Still further benefits and advantages of the present invention will become apparent to those skilled in the art upon a reading and understanding of the preferred embodiments.